How to make a projector for under $100
This is a simple guide on how to turn a few common products into your very own projector. Depending on your budget and skill level, you can choose to make the simplest 480p output, low light for dark rooms, or a higher end 720p that is viewable during the day. To make this projector you will need a few parts and about three to four hours of your time.Parts list
- LCD 15” or smaller panel with all logic boards
- Overhead projector (like the one used in high school math class)
- 1 or 2 Fan(s)
- Cardboard box, at least 2 sq ft
- Sharpie or magic marker
- Tape measure
- Roll of duct tape
- Set of spacers, I used a piece of my LCD casing
First step is to acquire your parts. For me, ebay was the fastest, cheapest and easiest way to source my parts. Here was my list:
Yes, I said that you can do it for under $100. To keep it under $100, don’t buy a LCD without the power brick if it needs one (made that mistake), also buy a cheaper projector. Now to discuss what you should buy.
A 15” or smaller LCD panel. If you can find a portable DVD player screen for cheap, jump on that. They normally are very small, meaning the whole thing will fit on the projector lens. Portable DVD players also usually have a composite video in source as well. Drawbacks include being limited to 480p and cost. Most projectors are about 11” square, with rounded corners. A 15” LCD at 4:3 ratio is about 9” high and 12” wide. You will have part of the screen NOT shown on your wall if you use a 15” LCD. My projector shows about 800x800 pixels, with the corners taking about 20 pixels from each side. It’s less than ideal, but it still looks great for movies. So, in closing, if you get a 15” panel, expect a resolution on the wall of about 700x700 to 900x900 depending on the model.
Projector. This is the part that can cause troubles. You need to decide how much you want to spend, and how good of a projector you want. Lumens rated for overheads are different that DLP projectors, so don’t try to compare the two. If you are going to be using this in a very dark room and don’t mind a slightly dim image, or just want to be as cheap as possible, then a 2,000 lumens rating projector will work well for you. If you ever want to use this projector during the day, I would suggest a 3,500 to 4,500 or higher lumens projector. My model, the 3M 9700 is rated at 4,300 lumens. Another feature that I like about mine is that it has two bulbs inside of it. If one burns out, you simply turn a knob, and it switches over to a different bulb. It also allows for different wattage bulbs, so if you want to use a lower power (~300w) instead of the full power bulb (450w) you can do that. Finally, it has two 110v outlets on the back which can support up to 5A draw. This is plenty for the LCD screen and the computer/fan you will be using.
I can’t write a better list then this one, and it’s one that I trust: http://louisville.edu/~wchall01/diyp.../overheads.htm
I would HIGHLY recommend the 3M 9700. With two bulbs, 4,300 lumens and being portable (it’s lighter) makes it great for this use. It’s also very cheap (list price was $500) on Ebay.
For my fan I choose a box fan because I’m lazy and don’t want to wire up a pair of 12cm fans. The box fan I use is quieter than the projector’s fan, and it keeps it nice and cool, so I can’t complain. 12cm or even 8cm fans are a great choice, but you'll need a PSU to run them. A box fan is bigger, but runs at 110v AC.
- Test the projector. If you have more than one bulb, try both. Leave it running on it’s own (stay close by) for 30-45 minutes. Make sure the fan works.
- Test your LCD panel in the casing. If you bought it from Ebay make sure it works before taking it apart. If it doesn’t work after you take it apart and you didn’t test it beforehand, you’ll have no idea if it never worked, or if you broke it.
- Carefully dissemble your LCD screen. The flat ribbon cable that connects from the logic boards to your panel is very fragile, and impossible to replace, so DON’T break it!
- Inside the casing you should have an input source board, a inverter for the backlight CCFL tubes and a power PCB. Disconnect the inverter board and wiring, we won’t use that at all.
- Now is the time where we use a spacer. I used the front plastic panel from my casing as the spacer. Setting it down turned 90 degrees with the screen across the thinner part made a perfect height spacer.
- Mount the LCD panel on top of the spacer. I didn’t even glue or tape it down, so it’s free to move for slight adjustments if necessary. You’ll need to find a spot for your PCBs at this point. I have them held up by a small cardboard box I cut and duct taped together.
- Turn on the projector and cover up any light spots on the top of the panel. If you can see light, put cardboard over it and duct tape it to the projector. I choose to leave the LCD untapped so it can move a bit when needed.
- Decide on an airflow path and set up your fan(s). You’ll need an intake and exhaust opening. Use more cardboard to cover up any light that spills out from any side that isn’t your intake or exhaust.
- Connect your PC and set the LCD to the highest resolution possible.
- I have my screen positioned so the right edge of the Start button (using XP) is just visible. This way I get the most of my desktop space.
- Position your video player in the screen and enjoy your new projector!
- Run the system for 30-45 minutes and confirm that everything is working like it should.
- Check the temperature of the LCD panel every couple of minutes with the back of your hand. If it’s too hot to touch, then you need better cooling. If it’s cool or room temperature, you can probably lower your fan speed/noise. Be sure to check often. Brown spots or other colorations are heat damage, which can wreck your panel in a matter of minutes.
- Basic safety check. These overheads can easily use 500w and output that in roughly a single square foot of space. These can be a fire hazard. Don’t blow your circuits. Keep small children away from it.
That's it! Feel free to ask questions or submit suggestions. Enjoy!